The present invention relates generally to deployable truss structures and more specifically to a tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure.
The Space Shuttle Transportation System developed by the National Aeronautics and Space Administration has greatly facilitated the research and development of both small and large space structures. Projects presently under consideration include extremely large antennae for communications or Earth surveillance, orbital laboratories, and space-based manufacturing facilities. These missions will be characterized by a need for linear structural members, such as the tetrahedral beam, which are automatically deployable and capable of varying geometry during use.
A variety of expandable and deployable structures for both space and terrestrial applications are found in the prior art. Hedgepeth et al (U.S. Pat. No. 4,334,391) discloses a deployable lattice column comprised of longerons connected together by diagonals and battens. The column can be compactly packaged, then erected into a structurally sound column. Additionally, the column employs redundant structural members to preserve integrity should some elements fail.
Although the Hedgepeth column, as well as many others, have enjoyed commercial success, a deployable column which is maneuverable in a direction other than along its axis has yet to be demonstrated. None of the deployable beams found in the prior art are capable of varying the shape of their axes so as to function, for example, as a remote manipulator arm. Manipulator arms presently in use are designed to resemble human arms; they have rigid sections connected by flexible joints. Such manipulator arms do not provide the strong, stable structure provided by the present deployable and manipulatable tetrahedral beam structure.
It is therefore an object of the present invention to provide a novel structural column comprised of repeating units of tandem tetrahedra.
It is a further object of the present invention to provide a novel joint for flexibly joining tetrahedral beam structural members.
Another object of the present invention is to provide a tetrahedral beam which can be compactly packaged and remotely deployed.
An additional object of the present invention is to provide a deployable beam that does not require a separate canister or deployer.
Yet another object of the present invention is to provide a tetrahedral beam capable of widely varying the shape of its central axis so as to enable it to function as a remotely controlled manipulator arm.
A further object is to provide a stable beam comprised of fewer structural members per unit length than prior art truss beams.